“They just told me, ‘You have a new guy named DuJuan, and he’ll be in there today,’ ” Van Pelt said. “He was just different than other body types we’ve had, which is good. Once he stepped on the practice field that first week, it was, ‘OK, I see something to him.’ He’s a talented runner.”

Harris has come out of practically nowhere—a job selling cars at a Jacksonville, Fla., Chrysler-Jeep-Dodge dealership to be precise—to become the lead back in the Packers’ post-season offense. When the Packers face the San Francisco 49ers on Saturday night in a divisional playoff game, Harris will be an integral part of the offense.

He jumped ahead of Alex Green, Ryan Grant and James Starks in a little more than a month since joining the team’s practice squad on Oct. 24. Harris originally was signed as protection after Cedric Benson suffered a Lisfranc fracture in his foot, but when Starks went out with a knee injury, Grant was signed and Harris was elevated to the 53-man roster.

In the 5 1/2 weeks he was on the practice squad, Harris opened eyes serving both as a look-team cornerback for the offense during walk-throughs and a running back for the defense during the full practice. With his Rubik’s Cube body frame, stylish dreadlocks and bouncy competitiveness, Harris quickly became a favorite among his teammates.

“He’s kind of a Transformer,” quarterback Aaron Rodgers said. “There’s more than meets the eye with DuJuan. He’s a very tough guy. He’s got great athleticism, agility; he makes some great jump cuts. ... He’s done some nice things for us.

“You have to give him a lot of credit. He’s learned the offense the last few weeks and studied, obviously, and the package for him is just going to continue to grow.”

Harris made his debut at home against Detroit, getting the ball on his first play from scrimmage because coach Mike McCarthy wanted to get a look at him the week before against Minnesota but never found the right place to insert him.

A Lambeau Field crowd was witness to Harris’ explosiveness when, after taking the handoff from Rodgers, Harris burst through the line for an 11-yard gain. He finished with 31 yards on seven carries, including a 14-yard touchdown run that put his tremendous leg strength on display during his first Lambeau Leap.

Harris continued to have an impact in victories over Tennessee and Chicago, busting loose for 70 yards rushing and 17 yards receiving in a season-ending loss to the Vikings. He followed that performance with 100 total yards and a touchdown in a wild-card rematch with Minnesota.

“Since I’ve been here, I’ve just been trying to help the team win,” Harris said. “Even when I was on the practice squad, I was trying to give them a real look. My mindset hasn’t changed.”

Harris has come a long way since joining the Jacksonville Jaguars as an undrafted free agent out of Troy. He spent most of 2011 on the Jaguars’ practice squad, working his way onto the 53-man roster late in the year and rushing nine times for 42 yards.

But the Jaguars cut him at the end of training camp and Pittsburgh, who claimed him on waivers, cut him four days after that. He was unemployed until Packers pro personnel director Eliot Wolf called him and offered him a job on the practice squad.

Harris had just begun selling cars, but his employer, who hired other NFL players in the past, understood.

Upon arriving in Green Bay, Harris received intensive one-on-one tutoring from Van Pelt. The two basically started out the way the other backs had in training camp and went over everything from how the holes in the line are numbered to which calls mean the play is going right and which mean it is going left.

“He’s been sharp in the meetings,” Van Pelt said. “There’s common mistakes in the system that a new guy will make, just little wrinkles here and there. He’s not a repeat offender, which is what you’re looking for. He’s learning. Once you correct it, it’s usually cleaned up for that week’s game until there’s another wrinkle.”

Pass protection has been the hardest thing for Harris to learn, but he's a willing blocker. In the wild-card game, he began catching check-down passes from Rodgers and turning them into substantial gains.

The Packers are hoping this aspect of his game will help them attack the open zones in Cover-2 defenses, although the 49ers don’t play the traditional Tampa-2 and won’t be as susceptible to those routes. Harris is likely to split time with Starks, who is expected to make his return this weekend. Harris will get first crack, and if he's effective, could render the other backs unnecessary.

Regardless of what happens Saturday night, Harris knows one thing is for sure: He’s going back to selling cars when the season is over. They’ve been doing good business there recently, and he is determined to sell his first. He isn’t one to give up easily.

“I just got off the phone with them—they just told me they sold 10 cars,” Harris said. “That’s live. That is live. Why not be a part of that?”